WASHINGTON  More than 75 senators are demanding a vote on a river navigation project that faces resistance from the White House.

The lawmakers sent a letter this week to Senate Majority Leader Bill Frist, R-Tenn., urging consideration of the Water Resources Development Act, despite a lack of support in President Bush's budget proposal.

The $10 billion spending bill -- which includes $3.6 billion to expand locks and pay for ecosystem restoration along the upper Mississippi and Illinois rivers -- was approved in the House by a wide margin last year.

Barge operators and farm groups have long pushed for construction of seven new 1,200-foot locks to replace outdated locks half that size and help speed grain transportation to markets. Environmental and taxpayer groups oppose the plan as wasted money, pointing to a steep decline in barge traffic over the past 15 years.

In President Bush's budget proposal released Monday, the Office of Management and Budget recommends spending only $27 million on maintenance projects to keep the old locks working and eliminates funding for preliminary design and engineering work on the lock expansion project.

The OMB said the U.S. Army Corps of Engineers "has concluded that the existing locks can continue to process tows safely and reliably for the next 50 years or more, as long as we continue to invest prudently in their maintenance and rehabilitation."